Women with the potentially cancer-causing human papillomavirus, or HPV, may be putting their partners at risk if they share sex toys during intimate relations, a new study suggests.

Researchers gave 12 women two vibrators each and detected the virus immediately after self-use on at least one of the vibrators used by all nine participants who tested positive for HPV.

Lead author Dr. Teresa Anderson, from the Indiana University School of Medicine in Indianapolis, said the small study is the first to examine whether vibrators could be transmitting the virus between sex partners.

"Sex toys used between partners within the same sexual encounter have the potential for transmitting HPV," Anderson told Reuters Health. "Cleaning the sex toy has the potential to decrease the amount of HPV DNA we can detect and so can potentially decrease the risk of transmission."

Genital HPV is the most common sexually transmitted infection in the United States. It is so pervasive that it has been called the common cold of the sexually active world.

HPV can be innocuous, but sometimes leads to warts and sometimes to cancer. The U.S. Centers for Disease Control and Prevention (CDC) estimates the virus causes an estimated 27,000 cervical, vulvar, vaginal, anal, penile, head and neck cancers among Americans each year.

The CDC recommends girls get one of two series of vaccines to protect against the type of HPV that causes most cervical cancers. Despite a push to immunize, less than 54 percent of U.S. girls between 13 and 17 years old were vaccinated in 2012.

The CDC also recommends that boys get one of the vaccines.

Current study participants were women between the ages of 18 and 29 who had engaged in sexual relations with both a man and a woman during the prior year. Anderson said she did not know if the participants had been vaccinated against HPV.

The investigators gave each woman a cleaning product, one vibrator made of thermoplastic elastomer - known as a "Rabbit"-style vibrator - and another made of soft silicone. They asked participants to swab the vibrators after vaginal use, immediately after cleaning and 24 hours later.

Nine of the participants tested positive for HPV, and the virus was detected on at least one of the two vibrators given to each of them. Just after use, HPV was found on all but one of the thermoplastic vibrators and on six of the nine silicone vibrators.